Narrow band emission from lithographically defined photonic bandgap structures in silicon: Matching theory and experiment

The authors previously reported discovery of narrow, thermal emission bands from symmetrically patterned features etched into silicon wafers. Emitted wavelengths corresponded to the geometrical size and spacing of the lithographically defined features. In this paper, we report further results that show the measured absorption peaks for such patterned surfaces match theoretical calculations of the complete electrodynamic problem solved using the Transfer Matrix Method (TMM). Calculations were used to optimize pattern geometry to obtain high-power emission in a single, narrow spectral band. Improved experimental performance was achieved with addition of a thin, patterned metal layer on top of the silicon. This more complex geometry was more clearly modeled by including surface plasmon resonances. Data and calculations are presented for variations with feature size, etch depth, substrate resistance, and rounding of feature corners. These results augur a new class of tunable infrared emitter devices with hundreds of milliwatts of power in a narrow spectral bandwidth.